Environment and Environmental Hygiene (Water) Questionbank 1


 MULTIPLE CHOICE QUESTIONS

 Safe and wholesome water is defined as the water that is
a. free from pathogenic agents
b. free from harmful chemical substances
c. pleasant to taste
d. usable for domestic purposes
e. all the above
ANS: e
Rain water is very soft water containing __________ per cent of dissolved solids
a. 0.00005
b. 0.0005
c. 0.000005
d. 0.005
ANS: b
The area draining into the reservoir is called as __________
a. Collection area
b. Attached area
c. Catchment area
d. Draining area
ANS: c
Agents of self purification in river include __________
a. Dilution and sedimentation
b. Aeratiuon and Oxidation
c. Sunlight, plant and animal life
d. All the above
ANS: d
Salt content in sea water is __________ percent
a. 7.5
b. 6.5
c. 3.5
d. 2.5
ANS: c
Deep wells tap water from __________
a. Water above the first impervious strata
b. Water from first porous strata
c. Water below the first impervious strata
d. Water below the second impervious strata
ANS: c
Katcha wells and Pucca wells are examples for __________
a. Tube wells
b. Dug wells
c. Step well
d. None of the above
ANS: b
__________ disease is a public health problem in areas where step wells are in use.
a. Cholera
b. Taeniais
c. Guinea worm
d. E. coli
ANS: c
To avoid bacterial contamination a sanitary well should be located __________ from likely sources of contamination.
a. 15 m
b. 50 feet
c. 10 m
d. both a &b
ANS: d
A sanitary well should have a parapet wall of at least __________ height above the ground.
a. 90-95 cm
b. 70-75 cm
c. 50-55 cm
d. 100-110 cm
ANS: b
Hardness of water appears to have a beneficial effect against __________ diseases
a. Neurological
b. Cardiovascular
c. Muculoskeletal
d. Reproductive
ANS: b
Water (Prevention and Control of Pollution) Act was passed in the year __________
a. 1974
b. 1964
c. 1978
d. 1968
ANS: a
The optimum period of storage of river water for purification is __________ days
a. 1-2
b. 3-7
c. 8-9
d. 10-14
ANS: d
Which among the following is not a part of slow sand filter or biological filter
a. supernatant (raw) water
b. a bed of graded sand
c. an under-drainage system
d. a system of filter control valves
e. none of the above
ANS: e
The depth of supernatant water above the sand bed in slow sand filter is __________ metre
a. 0.5-1
b. 1-1.5
c. 2-3
d. 3-5
ANS: b
Supernatant water provides a waiting of __________ hours, depending on the filtration velocity
a. 1-2
b. 3-12
c. 12-24
d. 24-48
ANS: b
The effective diameter of sand grains in slow sand filter is __________ mm
a. 0.2-0.3
b. 0.4 -0.7
c. 0.8-1
d. 1-1.5
ANS: a
The rate of filtration of water in case of a biological filter normally lies between __________ cubic metre/hour/per square metre of sand bed surface.
a. 0.1-0.4
b. 0.02-0.04
c. 5-15
d. 20-25
ANS: a
Ripening of biological filter means __________
a. completion of purification
d. time to close down the filter plant
c. formation of vital layer/schmutzdecke/zoogleal layer or biological layer
d. removal of vital layer/schmutzdecke/zoogleal layer or biological layer
ANS: c
Heart of biological filter is __________
a. vital layer
b. gravel support
c. filter control
d. under-drainage system
ANS: a
Venturi meter of the regulation system in the slow sand filter measures __________
a. rate of filtration
b. rate of oxidation
c. bed resistance or loss of head
d. rate of reduction in BOD
ANS: c
Which among the following statements are wrong?
a. Paterson’s filter is a gravity type rapid sand filter
b. Candy’s filter is a pressure type rapid sand filter
c. Alum is used as a chemical coagulant
d. Rapid sand filter is also known as biological filter
ANS: d
The correct sequence of steps in rapid sand filtration is as :
a. coagulation, rapid mixing, flocculation, sedimentation, filtration
b. rapid mixing, coagulation, flocculation, sedimentation, filtration
c. flocculation, coagulation, rapid mixing, sedimentation, filtration
d. coagulation, rapid mixing, flocculation, filtration, sedimentation
ANS: a
The time allotted for sedimentation in case of rapid sand filter is __________ hours
a. 0.5-1
b. 2-6
c. 8-10
d. 12-24
ANS: b
The effective diameter of sand grains in rapid sand filter is __________ mm
a. 0.2-0.3
b. 0.4 -0.7
c. 0.8-1
d. 1-1.5
ANS: b
The rate of filtration of water in case of a biological filter normally lies between __________ cubic metre/ square metre/hour
a. 0.1-0.4
b. 0.02-0.04
c. 5-15
d. 20-25
ANS: c
Which among the following statements are wrong?
a. Washing of slow-sand filter is by scrapping the sand bed
b. Washing of rapid sand filter is by back-washing
c. Loss of head allowed in slow sand filter is 4 feet
d. Loss of head allowed in rapid sand filter is 6-8 feet
e. None of the above
ANS: e
Rapid sand filter removes __________ per cent of bacteria
a.90-95
b.95-96
c. 98-99
d.99.9-99.99
ANS: c
Slow sand filter removes __________ per cent of bacteria
a.90-95
b.95-96
c. 98-99
d.99.9-99.99
ANS: d
Which among the following are the properties of chlorine?
a. kills pathogenic bacteria and aids coagulation
b. oxidises iron, manganese and hydrogen sulphide
destroys some taste and odour producing constituents
d. controls algae and slime organisms
e. all the above
ANS: e
the disinfecting action of chlorine is mainly due to __________
a. Hypochloric acid
b. Hypochlorous acid
c. Hypochlorite ion
d. Hydrochloric acid
ANS: b
Chlorine act best as a disinfectant when the pH of water is around __________
a. 9
b. 10
c. 7
d. 5
ANS: c
The difference between the amount of chlorine added to the water, anfd the amount of chlorine remaining at the end of a specific contact time at a given temperature and pH of water is called as __________
a. Break point
b. Chlorine demand
c. Residual chlorine
d. Superchlorination
ANS: b
The usual contact time of chlorination of water is __________ minutes
a. 30
b. 60
c. 120
d 180
ANS: b
The point at which the chlorine demand of the water is met or the point at which at which all combined chlorines have been disappeared and residual chlorine appears is called __________
a. Break point
b. Chlorine demand
c. Bleaching
d. Superchlorination
ANS: a
Chlorine has no effect on __________ at usual doses.
a. Spores
b. Protozoal cysts
c. Helminthic ova
d. All the above
ANS: d
The minimum recommended concentration of free chlorine is __________ mg/L for one hour
a. 0.5
b. 1
b. 5
c. 10
ANS: a
Paterson’s chloranome is a device used for measuring, regulating and administering __________ to water supplies.
a. Chloramine
b. Perchloron
c. Chlorine gas
d. Bleaching powder
ANS: c
__________ are loose compounds of chlorine and ammonia
a. Chloramine
b. Perchloron
c. Chlorine gas
d. Bleaching powder
ANS: a
Perchloron or high test hypochlorite ( H.T.H) is a __________ compound which carries 60-70 per cent of available chlorine.
a. Calcium
b. Magnesium
c. Sodium
d. Potassium
ANS: a
The type of chlorination suitable for heavily polluted water is __________
a, Break-point chlorination
b. Superchlorination
c. Chloramine
d. Perchloron
ANS: b
Which among the following statements regarding orthotolidine test is wrong?
a. Enables both free and combined chlorine in water to be determined
b. OT reacts with free chlorine instantaneously but reacts more slowly with combined chlorine producing yellow color
c. OTA ( Orthotolidine-Arsenite test) is a modification of of OT test to determine the free and combined chlorine seperatedly
d. The errors caused by the presence of nitrates, iron and manganese which also produce yellow color are overcome by OTA test
e. OT test was developed in 1938
ANS: e
The contact time in case of ozonation is __________ minutes
a. 1-5
b. 10-20
c. 30-60
d. 60-120
ANS: b
The dose of ozone in case of ozonation is typically in the range of __________ mg/L
a. 0.5-1
b. 1-2
c. 2-5
d. 6-10
ANS: c
Typical operating pressure in case of reverse osmosis is in the range of __________ bar.
a. 1-5
b. 5-10
c. 15-50
d. 50-100
ANS: c
Reverse osmosis rejects monovalent ions and organics of molecular weight greater than about __________ daltons.
a. 10
b. 50
c. 100
d. 200
ANS: b
Which among the pore size of the membranes is not matching with the membrane process?
a. Reverse osmosis : < 0.002 micron
b. Nanofiltration: 0.001-0.01 micron
c. Ultrfiltration: 0.002-0.03 micron
d. Microfiltration: 0.01-0.12 micron
e. None of the above
ANS: e
Bleaching powder or chlorinated lime contains a __________ per cent of available chlorine.
a. 23
b. 33
c. 37
d. 43
ANS: b
Halazone tablet is a __________ containing tablet
a. Chlorine
b. ozone
c. Amine
d. Potassium permanganate
ANS: a
__________ is used for the emergency disinfection of water
a. Chlorine
b. Ozone
c. Iodine
d. Radiation
ANS: c